code: def algebra_simplify(
      alphabet_size=26, min_depth=0, max_depth=2, nbr_cases=10000
  ):
      """Generate the algebra simplify dataset.
  
      Each sample is a symbolic math expression involving unknown variables. The
      task is to simplify the expression. The target is the resulting expression.
  
      Args:
        alphabet_size: How many possible variables there are. Max 52.
        min_depth: Minimum depth of the expression trees on both sides of the
            equals sign in the equation.
        max_depth: Maximum depth of the expression trees on both sides of the
            equals sign in the equation.
        nbr_cases: The number of cases to generate.
  
      Yields:
        A dictionary {"inputs": input-list, "targets": target-list} where
        input-list are the tokens encoding the expression to simplify, and
        target-list is a list of tokens encoding the resulting math expression after
        simplifying.
  
      Raises:
        ValueError: If `max_depth` < `min_depth`.
      """
      if max_depth < min_depth:
          raise ValueError(
              "max_depth must be greater than or equal to min_depth. "
              "Got max_depth=%s, min_depth=%s" % (max_depth, min_depth)
          )
  
      alg_cfg = math_dataset_init(alphabet_size, digits=5)
      for _ in range(nbr_cases):
          sample, target = generate_algebra_simplify_sample(
              alg_cfg.vlist,
              list(alg_cfg.ops.values()),
              min_depth,
              max_depth,
          )
          yield {
              "inputs": alg_cfg.int_encoder(sample),
              "targets": alg_cfg.int_encoder(target),
          }
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from collections import namedtuple
  import random
  import six
  from six.moves import range
  import sympy
label_desc: Use image node_id 11 for calling a global function with example usage: algebra_simplify(alphabet_size, min_depth, max_depth, nbr_cases) without return types